part of part of vasculature systemic venous system FMA:45626 In human anatomy, the systemic venous system refers to veins that drain into the right atrium without passing through two vascular beds (i.e. they originate from a set of capillaries and do not pass through a second set of capillaries before reaching the right side of the heart). The term systemic venous system is often used to differentiate veins from veins that drain the pulmonary system (the pulmonary venous system) and veins that drain the digestive tract (the portal venous system). Large veins that are considered part of the systemic venous system are the: Superior vena cava; Inferior vena cava[WP] Subdivision of cardiovascular system which has as its parts the right side of heart, the superior vena cava and the inferior vena cava[FMA] The appearance of Chordata and subsequently the vertebrates is accompanied by a rapid structural diversification of this primitive linear heart: looping, unidirectional circulation, an enclosed vasculature, and the conduction system.[well established][VHOG] The part of the venous system that drains the general body tissues[Kardong] UBERON:0004581 systemic venous circulatory system uberon venous system